The Neuroanatomical Core will continue to provide essential services for each of the six projects comprising this program. There will be four components of the services provided by the core: 1) standard histological stains, including Nissl, Weigart, Timms, Bodian, and Fink-Heimer; 2) equipment and reagents for the immunocytochemical localization of antigens in frozen or paraffin sections of neural tissue; 3) facilities and equipment for the localization of mRNA species by in situ hybridization; and 4) facilities and reagents for ultrastructural studies at the electron microscopic level, including immunoelectron microscopy and quantitative analyses. The first three of these components have been made available in the laboratory of Dr. Dodd; the EM studies are performed in a second facility operated by Dr. Bailey. Drs. Dodd and Bailey have extensive relevant experience in the methodologies to be employed. They will also make decisions on the purchase and use of reagents and equipment, and they will meet as often as is necessary to evaluate the services provided by the core. The expected use of the core services by individual projects is detailed. The Behavioral Core will be headed by Dr. Hawkins and will continue to provide a variety of behavioral tests to explore learning capabilities in transgenic mice and different strains of wild-type mice for comparison. These facilities have contributed significantly to each of the six projects. The core currently has facilities for several tests of hippocampal-dependent (explicit) learning in mice (e.g., Morris water maze, radial arm maze, object recognition). In addition, the core has tasks of implicit memory (e.g., a cued version of the Morris water maze, taste aversion, odor potentiated startle). Finally, the core plans to develop additional tests of both hippocampal-dependent and-independent learning (e.g., delayed non-match to sample, visual paired comparison, and higher-order aspects of classical conditioning). Not all projects make use of this core, but it is essential given the overall aims of the Center. These are continuing cores that have provided infrastructure support during the past five years. The rationale for the core is that centralizing these functions should lead to consistency in technology across projects and economies of scale of operation. Both of these core components are justified by the aims of the Center